Man arrested over fatal stabbing in Sydney's east

A man has been stabbed to death and a woman injured in Sydney's east after another man allegedly forced his way into a unit.

Police say a man and woman were inside a Darling Point unit when another man tried to break in just after 11.00am (AEDT) this morning.

Officers believe he had been in a relationship with the 28-year-old woman inside.

He allegedly eventually forced his way in and the man and woman inside were injured in an altercation.

He then fled from the scene.

Acting Police Superintendent Damian Henry says it is unclear exactly what happened inside the apartment, but the man has now handed himself in to police.

"There is a man under arrest at St Mary's police station who is currently assisting police and there's also an extensive crime scene examination going on," he said.

"There is a domestic relationship, the female and the man at St Marys but the full extent of those arrangements it's early in the investigation, yet to be determined."

"There are some reports from neighbours about a man trying to enter the unit. We're appealing for anybody who might have seen or heard anything to contact Crimestoppers, exactly what happened is still yet to be determined."

The 30-year-old man injured in the apartment died at the scene after being stabbed several times.

The woman is being treated in hospital for minor injuries.

Police are searching for a weapon and the apartment block is being treated as a crime scene.

You have no doubt been hearing a lot about the Paris Agreement and know that it pertains to climate change, but are too embarrassed at this stage to ask for an overall explanation of what it's all about.